(a) Field of the Invention
The present invention relates to a piezoelectric driving circuit that drives a piezoelectric element and a method for driving the piezoelectric driving circuit.
(b) Description of the Related Art
A piezoelectric element can convert electric energy to mechanical energy and can convert mechanical energy to electric energy. A full-bridge driving circuit is used to drive the piezoelectric element.
The full-bridge driving circuit supplies a square-wave voltage to the piezoelectric element. For example, the full-bridge driving circuit supplies a first DC voltage in a positive direction and a negative direction to the piezoelectric element. Thus, the square-wave peak-to-peak voltage supplied to the piezoelectric element is two times the first DC voltage.
In this case, when the first DC voltage is supplied to the piezoelectric element in the positive circuit, a current charging the piezoelectric element flows, and when the first DC voltage is supplied to the piezoelectric element in the negative direction, a current that discharges the piezoelectric element flows. The charging current and the discharging current are mostly used to charge and discharge a capacitor that forms the piezoelectric element. That is, whenever a direction of the voltage supplied to the piezoelectric element t is changed, the peak current that charges or discharges the capacitor of the piezoelectric element is generated.
Then, power consumption and noise are increased due to the charging and discharging of the capacitor.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.